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Home > News > Content
Steaming Machine Effectiveness Oct 31, 2017

The steam engine is a reciprocating power machine that converts the energy of the steam into mechanical work. The emergence of the steam engine has caused the 18th century industrial revolution. Until the beginning of the 20th century, it was still the most important motive in the world, and later gradually let the internal combustion engine and steam turbine.

The steam engine needs a boiler that boils water to produce high-pressure steam, which can use wood, coal, oil or natural gas and even combustible waste as a heat source. Steam expansion drives the piston to work.

Steam engine mainly by the cylinder, base, piston, crank connecting rod mechanism, slide valve with steam institutions, speed control agencies and flywheels and other components. The cylinder and the base are stationary

In a steam boiler, the water is boiled into steam by burning. Through the pipeline steam was sent to the cylinder. The valve controls the time the steam reaches the cylinder, enters the slide valve chamber through the main steam valve and the throttle valve, and enters the left or right side of the cylinder alternately by the spool valve to push the piston movement. Steam in the cylinder to push the piston work, cooling the steam through the pipeline was introduced into the condenser to re-condense into water. This process is repeated during the steam engine movement.

The general steam engine has three cylinders to form a group. The steam engine directly converts the up and down movement of the piston into the rotary motion of the axle. The new steam engine also contains a small turbine, the steam from the cylinder can also use its waste heat in the promotion of the turbine to improve the efficiency of the entire drive device. The turbine is also connected to the propeller shaft of the ship.


The development of steam engines is first reflected in the improvement of power and efficiency, which in turn depends mainly on the improvement of steam parameters. The steam pressure of the initial steam engine was only 0.11 to 0.13 MPa, reaching 0.35 to 0.7 MPa in the early 19th century and 6 to 10 MPa in the 1920s. In the steam temperature, the end of the 19th century is not more than 250 ℃, and by the 1930s had used 450 ~ 480 ℃.


As for the efficiency of the initial continuous operation of the steam turbine steam, according to the total fuel heat efficiency of the total efficiency of not more than 3%; by 1840, the best total efficiency of the condensing steam engine up to 8%; to the 20th century, the maximum efficiency of the steam engine can reach 20 %the above.

Rotating speed

In terms of speed, the end of the 18th century Watt steam engine only 40 to 50 r / min; the early 20th century, the speed reached 100 to 300 r / min, the individual steam engine has reached 2500 r / min. In terms of power, the initial stand-alone power is only a few horsepower, the early 20th century, a marine steam engine power up to 25,000 horsepower.

With the steam parameters and power increases, the steam can no longer continue to expand in a cylinder, must also continue to expand in the connected cylinder, so there have been multi-stage expansion of the steam engine. Steam engine due to the limitation of the flash point of lubricating oil, the maximum temperature of the steam is generally not more than 400 ℃, locomotive, marine and other mobile steam engine is also slightly lower, most not higher than 350 ℃. Taking into account the possibility of expansion and structural economy, the commonly used pressure is below 2.5 MPa. Steam parameters are limited, and thus also limits the steam engine power to further improve.


The emergence and improvement of the steam engine to promote the socio-economic development, but at the same time the development of the economy in turn to the steam engine put forward higher requirements, such as the requirements of the steam engine power, high efficiency, light weight, small size. Despite the many improvements to the steam engine, its use and expansion of its performance, but with the development of steam turbines and internal combustion engines, the steam engine due to the existence of insurmountable weakness and gradually decline.